Cardinal Math

Addition with regrouping · sheet 12 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 51 + 39 90 80 forgets the ten810 writes the whole column sum
2 205 + 399 604 5914 writes the whole column sum594 forgets the ten694 carries two columns over
3 36 + 67 103 913 writes the whole column sum93 forgets the ten
4 193 + 166 359 1259 carries two columns over2159 writes the whole column sum259 forgets the ten
5 229 + 576 805 7915 writes the whole column sum795 forgets the ten895 carries two columns over
6 397 + 299 696 1686 carries two columns over51816 writes the whole column sum586 forgets the ten
7 318 + 449 767 7517 writes the whole column sum757 forgets the ten857 carries two columns over
8 307 + 406 713 7013 writes the whole column sum703 forgets the ten803 carries two columns over
9 168 + 184 352 1342 carries two columns over21412 writes the whole column sum242 forgets the ten
10 378 + 326 704 6914 writes the whole column sum694 forgets the ten794 carries two columns over
11 174 + 162 336 1236 carries two columns over2136 writes the whole column sum236 forgets the ten
12 13 + 48 61 51 forgets the ten511 writes the whole column sum
13 160 + 543 703 1603 carries two columns over603 forgets the ten6103 writes the whole column sum
14 32 + 29 61 51 forgets the ten511 writes the whole column sum
15 45 + 47 92 812 writes the whole column sum82 forgets the ten
16 514 + 207 721 711 forgets the ten7111 writes the whole column sum811 carries two columns over
17 24 + 37 61 51 forgets the ten511 writes the whole column sum
18 497 + 269 766 1756 carries two columns over61516 writes the whole column sum656 forgets the ten
19 13 + 88 101 91 forgets the ten911 writes the whole column sum
20 16 + 16 32 212 writes the whole column sum22 forgets the ten

Reading the wrong answers

One wrong answer is a slip. The same pattern on three or more problems is a rule your child is following, and it has a name and a fix in the guide. Problems marked "no pattern to catch" are the plain ones; a child who gets only those right is telling you something too.

Writes the whole column sum 20 of 20 problems

Writes each column's full total into the answer: 8 and 5 are 13, so 13 goes down; 3 and 4 are 7.

38 + 45 they write 713 it is 83

Forgets the ten 20 of 20 problems

Adds each column and keeps only the ones digit of the total. The ten that should move left gets dropped.

38 + 45 they write 73 it is 83

Carries two columns over 12 of 20 problems

The carried ten skips a column and lands two places left, where it's worth a hundred.

375 + 182 they write 1457 it is 557

Not sure which? The five-minute check picks the problems that tell the patterns apart and names the one it sees.